Small Engines (Lawn Mowers, etc.): B & S Model 10A902/Type 2189B3, vacuum leaks, adjustment screws

Question
Hello Fred! Thank-You in advance for your advice. I think what you are all doing here is great. If there were only more people willing to help others... I have a 5 yr old 4hp yard machine w/ B&S engine. One day it would not reach normal rpm, and eventually stalled with load. After 3-4 more mows, it would not start except when you first prime carb, as if it's not getting fuel. I replaced the diaphragm, gasket, and gov spring, used carb cleaner throughout, and compressed air. No obvious vacuum leaks. Starts after prime only still, but only at low rpm, and will stall within 15-20 seconds. There is no adjustment screws. If internal to carb, is it worth it to replace? Whole machine new was $145. Thanks for any input.   Jay

Answer
The first thing I would do is replace the fuel cap.  If it still happens after that check to see if there is a screen in the bottom of the fuel tank.  It could be obstructed.  Spray compressed air through all felines and primer lines.  When you hand to cover part.  You inspect the needle.  Sometimes the needle will stick in the seat and cause a problem like this.  If this is not it the next place I would go would be to head gasket, crankcase breeder and crankcase gaskets.  Good luck